Venturi Masks - With Dilutors or DialTransparent, molded vinyl mask features smooth edges Each mask features an adjustable nose clip and elastic strap Includes 7' of crush resistant, star lumen oxygen supply tubing 33070 33071: Includes seven dilutor jets for controlled oxygen therapy (Blue 24%, White 28%, Orange 31%, Yellow 35%, Red 40%, Pink 50%, Green 60%) 33072 33073: Features an adjustable dial with fixed oxygen concentrations ranging from 24% to 50% Not made with natural rubber